Impact of COVID-19 on Dental Care During a National Lockdown: a Retrospective Observational Study

International Journal of Environmental Research and Public Health

Article Impact of COVID-19 on Dental Care during a National Lockdown: A Retrospective Observational Study

Elias Walter * , Leonard von Bronk, Reinhard Hickel and Karin Christine Huth

Department of Conservative Dentistry and Periodontology, University Hospital, LMU, 80336 Munich, Germany; [email protected] (L.v.B.); [email protected] (R.H.); [email protected] (K.C.H.) * Correspondence: [email protected]; Tel.: +49-89-440059337; Fax: +49-89-440059302

Abstract: The coronavirus disease 19 (COVID-19) has challenged dental health professions. This study analyzes its impact on urgent dental care in the Department of Conservative Dentistry and Periodontology, University Hospital Munich and Bavaria, Germany. Patient numbers without and with positive/suspected COVID-19 infection, their reasons for attendance, and treatments were retrospectively recorded (February–July 2020) and linked to local COVID-19 infection numbers, control measures, and numbers/reasons for closures of private dental practices in Bavaria, Germany. Patient numbers decreased within the urgent care unit and the private dental practices followed by a complete recovery by the end of July. While non-emergency visits dropped to almost zero during the ﬁrst lockdown, pain-related treatments were administered invariably also in patients with positive/suspected COVID-19 infections. Reasons for practice closures were lack of personal protective equipment (PPE), lack of employees, staff’s increased health risks, and infected staff, which accounted for 0.72% (3.6% closures in total). Pain-driven urgent dental care remains a constant Citation: Walter, E.; von Bronk, L.; Hickel, R.; Huth, K.C. Impact of necessity even in times of high infection risk, and measures established at the beginning of the COVID-19 on Dental Care during a pandemic seem to have provided a safe environment for patients as well as oral health care providers. National Lockdown: A Retrospective PPE storage is important to ensure patients’ treatment under high-risk conditions, and its storage and Observational Study. Int. J. Environ. provision by regulatory units might guarantee a stable and safe oral health care system in the future. Res. Public Health 2021, 18, 7963. https://doi.org/10.3390/ Keywords: COVID-19; urgent dental care; lockdown; pandemic ijerph18157963

Academic Editors: Guglielmo Campus and Maria Grazia Cagetti 1. Introduction Emerging infectious diseases (EID) have increased in the last century due to socio- Received: 29 June 2021 economic factors such as population density and global trafﬁc [1]. One of those pathogens, Accepted: 24 July 2021 Published: 28 July 2021 a novel coronavirus causing the severe acute respiratory syndrome (SARS-CoV-2) [2], emerged at the end of the year 2019 in Wuhan, China. The resulting coronavirus disease

Publisher’s Note: MDPI stays neutral 19 (COVID-19) developed quickly toward a global pandemic and health crisis. After a with regard to jurisdictional claims in year, it is still ongoing, with over 300,000 reported cases per day worldwide and over published maps and institutional affil- 2,500,000 deaths in total as of 1 March 2021 [3]. The first patient in Germany was diagnosed iations. in Munich, and the city quickly became a hotspot in the country [4]. Similar to many other nations, the number of infections was reduced by, so far, two national lockdowns, which were accompanied by recommendations to suspend elective medical/dental care [5,6]. Such extensive measures are unprecedented in modern history and have unpredictable effects on medical specialties and their patients. Additionally, transmission via aerosols Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. and droplets [7,8], which are unavoidable for many dental procedures, as well as proximity This article is an open access article to and number of patients attended by dental staff comprise a high risk of infection. distributed under the terms and Nevertheless, dentistry has been considered an essential service during the pandemic, conditions of the Creative Commons but its impact on the profession and patients has not been evaluated yet [6]. The first Attribution (CC BY) license (https:// infection wave was followed by so far two others with higher infection numbers. Even creativecommons.org/licenses/by/ though vaccines became available in January 2021, the population remains in a state of 4.0/). uncertainty because of several new COVID-19 variants [9,10]. This uncertainty in the

Int. J. Environ. Res. Public Health 2021, 18, 7963. https://doi.org/10.3390/ijerph18157963 https://www.mdpi.com/journal/ijerph Int. J. Environ. Res. Public Health 2021, 18, 7963 2 of 12

development of the pandemic calls for a detailed analysis of demand for as well as specifics of dental treatment during the first infection wave in order to predict and plan dental care in the future [11]. Accordingly, a recent article asked for a consensus on the definition of essential oral health care and postulated a model with advanced, essential, basic, and urgent care [12]. The urgent care unit of the Department of Conservative Dentistry and Periodontology is one of the primary diagnosis centers for acute dental problems at the University Hospital Munich. At the beginning of the pandemic, a detailed report about the department’s safety measures against COVID-19 was published, but the effects and efficiency have not been evaluated yet. In the presented study, we analyzed patient development during the pandemic and evaluated the necessity of dental treatments. Therefore, the aim of this retrospective study was to record patient numbers without and with positive/suspected COVID-19 infections, their reasons for attendance, and associated treatments, and to link these data to local COVID-19 infection numbers, control measures, as well as numbers and reasons for the closures of private dental practices in Bavaria, Germany.

2. Materials and Methods 2.1. Study Design and Setting This retrospective observational surveillance study focused on the urgent outpatient care unit of the aforementioned department between February 1 and the end of July 2020. February was considered as baseline, as the public awareness toward COVID-19 was low. Patients could attend the urgent care unit spontaneously without appointment or prerequisites. Primary care was carried out. If necessary, patients were sorted to specific units for further care later on. The urgent care unit provides an optimal and stable setting to analyze patients’ flow before, during, and after the national lockdown. Other subunits within the same department—namely, the private outpatient care, pediatric dentistry, or special care—were not included in this study because their treatment spectrum is more complex. The teaching section switched from patient treatment to phantom head simulation to guarantee students safety and therefore was omitted. Additionally, the outpatient care of the oral and maxillofacial surgery and prosthodontics departments were not considered in this study. In comparison, the mean patient numbers during the same calendar weeks in the years from 2016 to 2019 were collected. The study was approved by the medical faculty ethics committee of the Ludwig-Maximilians-Universität, Munich (No. 20-0904). A detailed description of measures regarding the increased hygienic demands and requirements for social distancing during the COVID-19 pandemic has been given before [13]. In short, each patient was assessed for the likeliness of SARS-CoV-2 infection by a questionnaire before entering the clinic. They were asked if they presented symptoms that coincide with COVID-19, if they had traveled to a COVID-19 risk area, or if they have had close contact to a positive COVID-19 patient. Additionally, temperature was measured at a triage station at the entrance of the clinic. Upon a positive answer or increased temperature, the respective patient was treated in a separated unit by staff wearing increased personal protective equipment (PPE) [13]. During that time period, the testing infrastructure was not as advanced, and COVID-19 confirmation could often not be obtained before treatment in the urgent care unit. All other patients were treated under regular dental protective measures.

2.2. Data Acquisition All patients were asked for their reason of attendance before being admitted to the urgent care section. These reasons were recorded and afterwards categorized in pain, broken tooth or restauration, trauma, continued appointment, and checkup regarding simple questions such as dentin hypersensitivity. To date, these reasons represented the opinion/perception of each patient on their need of dental care regardless of professional dental diagnosis or the following treatment. Int. J. Environ. Res. Public Health 2021, 18, 7963 3 of 12

The following treatments were categorized into endodontic, restorative, periodontal, surgical, trauma, or pharmacological intervention. Each patient received a checkup, and patients without the need of immediate intervention were categorized into checkup. Multi- ple answers were possible if separate treatments independently of each other were needed in one patient. A distinct group of patients was referred from other medical departments, for example for identiﬁcation of unknown infection origins, before radio- or chemotherapy or general dental problems during the patients’ hospital stay. These were summarized by the category “inpatient consultation” regarding both reason of attendance as well as treatment. All data were collected in October 2020. To complete the picture of the necessity of urgent dental care, the following additional data were collected: ﬁrst, the number of positively tested COVID-19 cases in Munich according to the Robert Koch Institute (RKI) and the national health department in Ger- many [14] (collected 24 October 2020); second, governmental measures taken in Bavaria for infection control [15] (collected 24 October 2020); third, information about the number and reasons of practice closures in Bavaria and the amount of quarterly invoiced treatments in comparison to 2019 were kindly provided by the Bavarian Association of Statuary Health Insurance (KZVB) (15 December 2020). This was possible as practices that treat patients insured by the statutory health insurance are obliged to report closures to the KZVB. Rea- sons for closure were categorized into missing PPE, missing staff, administrative order, and others. Multiple answers were possible.

2.3. Statistics The software Microsoft Excel (16.43) (Microsoft, Redmond, WA, USA) was used for descriptive data analysis. Data were depicted in bar diagrams and pie charts using Photoshop 2020 (21.2.2) and Illustrator 2020 (24.3) (both Adobe, San Jose, CA, USA). For statistical analysis, data were grouped into pre-lockdown (3 February 2020 to 21 March 2020), lockdown (22 March 2020 to 25 May 2020) as well as post-lockdown (26 May 2020 to 31 July 2020). Mean and standard deviation were calculated for each group and statistically compared (Prism, GraphPad Software, San Diego, CA, USA). Gaussian distribution was tested by Shapiro–Wilk tests. If data were distributed normally, one-way ANOVA was used in conjunction with Bonferroni correction. Otherwise, the Kruskal–Wallis test with Dunn’s correction was used to determine signiﬁcance. Signiﬁcance was assumed at p ≤ 0.05.

3. Results 3.1. Patient Numbers during the COVID-19 Pandemic Firstly, the effect of the COVID-19 pandemic on patient volume was recorded (Figure1A) along with measures for infection control by the University Hospital (Figure1B) as well as the German government (Figure1C). In total, 3014 patients attended the urgent care unit between 3 February 2020 and 31 July 2020. Of these, 51% were male and 49% were female with an age range from 2 to 94 years and a median age of 54 years (Figure S1). The public awareness of SARS-CoV-2 at the beginning of March led to a quick decline in patient numbers. On 18 March, elective treatments were suspended by governmental order, while urgent dental care was maintained [13]. At this time, COVID-19 cases increased exponen- tially in Munich, and accordingly, the number of positive/suspected COVID-19 patients raised to a maximum of 5 patients with an average of 3.74 ± 1.67 per week for 6 weeks (Figure2A). The following week after the national lockdown showed the lowest number of patients receiving urgent dental care with only 46 patients (23 March to 30 March). This constitutes only 25% of the average patient volume in previous years (Figure2B ) and coincided with the government ordering the national lockdown on 22 March. The peak of COVID-19 cases was reached 8 days after introduction of the lockdown with 314 reported new cases per day in Munich on 31 March. Int.Int. J. J. Environ. Environ. Res. Res. Public Public Health Health 2021, 18, 7963x 45 of of 12 13

Figure 1. Patient numbers inFigure the urgent 1. Patient dental numbers care unit in along the urgent with measures dental care for unit infection along withcontrol measures during the for infectioninitial period control of the COVID-19 pandemic.during (A the) Weekly initial periodpatient of numbers the COVID-19 in the pandemic. urgent (dentalA) Weekly care patient unit and numbers patients in the with urgent positive/suspected COVID-19dental infections care unit from and 3 February patients to with 31 July positive/suspected 2020. In temporal COVID-19 context, the infections middle and from lower 3 February section to show corresponding (B) hospital and (C) governmental measures taken as precautions against COVID-19. Each measure 31 July 2020. In temporal context, the middle and lower section show corresponding (B) hospital and is given on the timeline (dotted line, each dot represents a day with weekly separation by vertical lines). The red line marks (C) governmental measures taken as precautions against COVID-19. Each measure is given on the the beginning of the national lockdown. timeline (dotted line, each dot represents a day with weekly separation by vertical lines). The red line marks the beginning of the national lockdown. Within the following three months, the number of patients recovered slowly. Accordingly, reported COVID-19 cases per day in Munich declined. During this time, elective treatments restarted on 5 May, 48 days after switching to solely urgent care, while positive/suspected COVID-19 patients declined to one every couple of weeks (Figure 2A). At this time, on average, 15 cases of COVID-19 were reported per day in Munich, and

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lockdown measures were loosened by the government and restaurants and stores were Int. J. Environ. Res. Public Health 2021, 18reopened., 7963 At the end of July, patients receiving urgent dental care normalized to around5 of 12 30 a day, similar to previous years, which showed a stable average of approximately 35 patients (Figure 2B).

Figure 2. Number of patientsFigure with 2. Number positive/s ofuspected patients withCOVID-19 positive/suspected infections concurrent COVID-19 infectionswith COVID-19 concurrent infections with COVID- in Munich and comparison of patient numbers with previous years. (A) Patients with positive/suspected COVID-19 19 infections in Munich and comparison of patient numbers with previous years. (A) Patients with infections solely in the urgent dental care unit per week (left axis, red) in comparison with officially registered COVID-19 positive/suspected COVID-19 infections solely in the urgent dental care unit per week (left axis, red) cases in Munich per week (right axis, grey) from 3 February to 31 July 2020. (B) Total patient numbers per week compared with patient numbers of thein years comparison 2016–2019 with in ofﬁcially the same registered calendar COVID-19 weeks (CW, cases mean in Munich± standard per deviation). week (right The axis, red grey) line from marks the beginning of the3 first February national to 31lockdown. July 2020. (B) Total patient numbers per week compared with patient numbers of the years 2016–2019 in the same calendar weeks (CW, mean ± standard deviation). The red line marks3.2. Reasons the beginning for Seeking of the Urgent ﬁrst national Dental lockdown. Care and Resulting Treatment

WithinThe reasons the following given by three the months, patients the for number attending of patients the urgent recovered dental slowly. care unit Accord- were ingly,recorded reported weekly COVID-19 (Figure 3). cases In February per day in 202 Munich0, which declined. was considered During this as baseline, time, elective these treatmentsreasons were restarted pain (25%), on 5 May,checkups 48 days for minor after switching questions to(26%), solely and urgent broken care, restorations while pos- or itive/suspectedbroken tooth (12%). COVID-19 Inpatient patients consultations declined a toccounted one every for couple17% of ofall weeksreasons; (Figure 15% of2A). the Atpatients this time, came on for average, continued 15 cases treatment, of COVID-19 which werehad been reported started per dayearlier. in Munich,Acute dental and lockdowntrauma constituted measures were5% of loosened the reasons. by the government and restaurants and stores were reopened. At the end of July, patients receiving urgent dental care normalized to around 30 a day, similar to previous years, which showed a stable average of approximately 35 patients (Figure2B).

3.2. Reasons for Seeking Urgent Dental Care and Resulting Treatment The reasons given by the patients for attending the urgent dental care unit were recorded weekly (Figure3). In February 2020, which was considered as baseline, these reasons were pain (25%), checkups for minor questions (26%), and broken restorations or broken tooth (12%). Inpatient consultations accounted for 17% of all reasons; 15% of the patients came for continued treatment, which had been started earlier. Acute dental trauma constituted 5% of the reasons.

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Figure 3. Reasons for seekingFigure urgent 3. Reasons dental care for seeking during urgentthe init dentalial period care duringof the COVID-19 the initialperiod pandemic. of the Patients´ COVID-19 reasons pandemic. for attending the urgent dentalPatients care´ reasonsunit were for categorized attending the into urgent checkup dental with care mino unitr were questions categorized (n = 507), into pain checkup (n = with1079), minor broken tooth/restauration (n = 588), continued appointment (n = 395), inpatient consultation (n = 381), and trauma (n = 64) questions (n = 507), pain (n = 1079), broken tooth/restauration (n = 588), continued appointment from 3 February to 31 July 2020. The first red line marks the beginning and the second marks the end of the national (n = 395), inpatient consultation (n = 381), and trauma (n = 64) from 3 February to 31 July 2020. The lockdown, dividing the time into pre-lockdown, lockdown, and post-lockdown. The red bars represent patients with high- risk of or confirmed COVID-19first redinfection line marks (ANOVA; the beginning * p ≤ 0.05, and ** p the≤ 0.01, second *** p marks ≤ 0.001). the end of the national lockdown, dividing the time into pre-lockdown, lockdown, and post-lockdown. The red bars represent patients with high-riskFrom of orMarch confirmed onwards, COVID-19 when infection the broad (ANOVA; public * p became≤ 0.05, **awarep ≤ 0.01, of ***thep pandemic,≤ 0.001). the patient numbers decreased, and elective treatments including checkups with minor From March onwards, when the broad public became aware of the pandemic, the pa- questions or second opinions were suspended, resulting in distribution changes of the tient numbers decreased, and elective treatments including checkups with minor questions remaining reasons. Continued appointments and checkups decreased to zero directly or second opinions were suspended, resulting in distribution changes of the remaining rea- after the lockdown and only recovered slowly. Only pain as a reason remained constant sons. Continued appointments and checkups decreased to zero directly after the lockdown with approximately 30 patients per week, which accounted for more than 50% of all and only recovered slowly. Only pain as a reason remained constant with approximately patients during the lockdown. Broken teeth or insufficient restoration as a reason 30 patients per week, which accounted for more than 50% of all patients during the lockdown.decreased Broken slightly teeth but or insufficientrecovered fast restoration with a slight as a reason overcompensation decreased slightly at the but beginning recovered of fastJuly withfor three a slight weeks. overcompensation Inpatient consul attations the beginning were only of mildly July foraffected. three weeks. Inpatient consultationsIn the following, were only the mildly actual affected. treatments were recorded and categorized (Figure 4). In FebruaryIn the (baseline), following, checkups the actual without treatments urge werent interventions recorded and categorizedwere the most (Figure prevalent4). In February(45%). Restorative (baseline), (15%), checkups endodontic without urgent(13%),interventions as well as surgical were the (17%) most treatments prevalent (45%). were Restorativeapplied to a (15%),similar endodontic extent. Less (13%), common as well were as acute surgical periodontal (17%) treatments therapy (5%) were and applied acute totrauma a similar treatment extent. (1%). Less Inpatient common wereconsultations acute periodontal were applied therapy in 14% (5%) of andall patients. acute trauma treatment (1%). Inpatient consultations were applied in 14% of all patients.

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Figure 4. Dental treatmentsFigure carried 4. outDental in the treatments urgent dental carried care outunit in during the urgent the initial dental period care unitof the during COVID-19 the initial pandemic. period of Treatments performed on patientsthe COVID-19 per week pandemic. in the urgent Treatments dental performed care unit onfrom patients 3 February per week to 31 in July the urgent 2020. Treatments dental care unit were categorized into endodontic (n = 410), restorative (n = 525), periodontal (n = 137), surgical (n = 410), trauma (n = 32), from 3 February to 31 July 2020. Treatments were categorized into endodontic (n = 410), restorative and pharmacological (n = 77) interventions as well as inpatient consultations (n = 370) or checkups with minor questions (n = 525), periodontal (n = 137), surgical (n = 410), trauma (n = 32), and pharmacological (n = 77) (n = 1160). The first red line marks the beginning and the second marks the end of the national lockdown, dividing the time into pre-lockdown, lockdown,interventions and aspost-lockdown. well as inpatient The consultations red bars represent (n = 370) patients or checkups with with high minor risk of questions or confirmed (n = 1160 ). COVID-19 infection (ANOVAThe or ﬁrst Kruskal–Wallis; red line marks * p the ≤ 0.05, beginning ** p ≤ 0.01, and *** the p second≤ 0.001). marks the end of the national lockdown, dividing the time into pre-lockdown, lockdown, and post-lockdown. The red bars represent patients with highDirectly risk of after or conﬁrmed the lockdown, COVID-19 infectioncheckups (ANOVA without or Kruskal–Wallis; practical intervention * p ≤ 0.05, ** droppedp ≤ 0.01, ***abruptlyp ≤ 0.001). from 45% to zero (Figure 4), meaning that all patients who attended the urgent care unit until 21 April needed urgent interventions. In detail, endodontic therapy was Directly after the lockdown, checkups without practical intervention dropped abruptly necessary on average in 19 patients per week before the lockdown, and it decreased from 45% to zero (Figure4), meaning that all patients who attended the urgent care unit afterwards by 42% to 11 patients on average per week by 15 June and returned to initial until 21 April needed urgent interventions. In detail, endodontic therapy was necessary on numbers thereafter. Nevertheless, endodontic therapy was the least affected treatment. average in 19 patients per week before the lockdown, and it decreased afterwards by 42% Restorative therapy decreased from 21 patients per week before the lockdown by 55% to to 11 patients on average per week by 15 June and returned to initial numbers thereafter. 10 patients afterwards and increased again to normal levels by 25 May with 22 patients Nevertheless, endodontic therapy was the least affected treatment. Restorative therapy per week on average. Similarly, surgical treatment decreased from 24 patients on average decreased from 21 patients per week before the lockdown by 55% to 10 patients afterwards to eight patients after the lockdown (67%) but did not recover fully in the recorded and increased again to normal levels by 25 May with 22 patients per week on average. timeframe. In July, only an average of 14 patients required surgical treatment per week. Similarly, surgical treatment decreased from 24 patients on average to eight patients after In contrast, acute periodontal therapy as well as trauma treatments remained constant. the lockdown (67%) but did not recover fully in the recorded timeframe. In July, only an Inpatient consultations also slightly decreased after the lockdown, assumingly because average of 14 patients required surgical treatment per week. In contrast, acute periodontal therapythe referring as well medical as trauma specialties treatments were remained affected constant.by COVID-19 Inpatient as well consultations and therefore also slightlyrequired decreased less dental after expertise. the lockdown, After 25 assumingly May, these because numbers the recovered referring medicalto similar specialties numbers wereas before affected (average by COVID-19 15 patients as weekly). well and therefore required less dental expertise. After 25 May, these numbers recovered to similar numbers as before (average 15 patients weekly).

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3.3. Treatments Performed on Patients with Positive/Suspected COVID-19 Infections 3.3. TreatmentsSolely within Performed the urgent on Patients dental care with unit, Positive/Suspected 33 patients with COVID-19 positive/suspected Infections COVID- 19 infectionsSolely within were the registered urgent dental between care unit,February 33 patients and July, with of positive/suspected which the majority COVID- (25 patients)19 infections attended were registered during the between period February of highest and July,COVID-19 of which prevalence the majority in (25Munich patients) in betweenattended 9 during March the and period 27 April. of highest Twenty-five COVID-19 of the prevalence 33 patients in showed Munich insevere between dental 9 March pain, whileand 27 all April. other Twenty-ﬁvereasons were of sparsely the 33 patientsrepresented showed (broken severe tooth/restoration: dental pain, while 3, continued all other appointment:reasons were sparsely2, inpatient represented consultation: (broken 1, trauma: tooth/restoration: 1, checkup: 1) 3, (Figure continued 5A). appointment: The resulting 2, treatmentsinpatient consultation: were endodontic 1, trauma: in most 1, checkup:cases (13), 1) whereas (Figure5 A).all other The resulting categories treatments appeared were less thanendodontic six times in each most (Figure cases (13), 5B). whereasIn only four all other COVID-19 categories patients appeared urgent less intervention than six times was noteach necessary, (Figure5B). which In only was four in early COVID-19 March, patients when emergency urgent intervention protocols waswere not not necessary, yet fully established.which was in early March, when emergency protocols were not yet fully established.

Figure 5. Reasons of attendanceFigure given 5. Reasons by patients of attendance with positive/suspected given by patients COVID-19 with positive/suspected infections and COVID-19 respective infections dental and treatments. Pie charts depictingrespective (A) reasons dental of treatments. attendance Pieand charts (B) treatments depicting of ( Apatients) reasons wi ofth attendancepositive/suspected and (B) COVID- treatments of 19 infections from 3 Februarypatients to 31 July with 2020. positive/suspected COVID-19 infections from 3 February to 31 July 2020.

3.4.3.4. Effects Effects of of COVID-19 COVID-19 Reported Reported for for Dental Dental Care Care in in Bavaria Bavaria TheThe Bavarian Bavarian Association Association of of Statuary Statuary Health Health Insurance Insurance (KZVB) (KZVB) reported reported that that during during thethe first ﬁrst national national lockdown, lockdown, up up to to 3.6% 3.6% of of their their contractual contractual dental dental practices practices were were closed. closed. OutOut of of these, these, 0.72% 0.72% were were closed closed by governmental order order because of a positive COVID-19 diagnoseddiagnosed staff member. OnOn 1111 May,May, only only 0.16% 0.16% closures closures were were still still recorded recorded in Bavaria.in Bavaria. As Asreasons reasons for closure,for closure, 66% of66% all of closed all closed dental practicesdental practices stated missing stated propermissing PPE proper including PPE includingregular facemasks regular facemasks and gloves, and 38% gloves, reported 38% lack reported of employees, lack of and employees, 20% reported and health 20% reportedrisk factors health such risk as immunosuppressionfactors such as immuno or hearthsuppression disease or during hearth the disease whole during timeframe the whole(Figure timeframe6A). (Figure 6A).

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Figure 6. Effects of the COVID-19 pandemic on Bavarian dental practices. (A) Reason for temporary Figure 6. Effects of the COVID-19 pandemic on Bavarian dental practices. (A) Reason for closure of dental practices in absolute numbers on 6 April 2020. (B) Invoiced treatments of patients temporary closure of dental practices in absolute numbers on 6 April 2020. (B) Invoiced treatments insured under a statutory insurance in Bavaria in the quarters Q1–Q3 in 2020 in percent of the same of patients insured under a statutory insurance in Bavaria in the quarters Q1–Q3 in 2020 in percent quarters in 2019. of the same quarters in 2019. The quantity of invoiced treatments in Bavarian practices regarding patients with publicThe insurance quantity may of beinvoiced indicative treatments of the impact in Bavarian of the pandemic practices on dentalregarding care inpatients Bavaria. with publicAccordingly, insurance a decrease may be of thoseindicative invoiced of the treatments impact ofof 4.7% the waspandemic reported on by dental the KZVB care in Bavaria.for the first Accordingly, quarter of a 2020 decrease (January of those to March) invoiced compared treatments to the of 4.7% same was quarter reported in 2019 by the KZVB(Figure for6B). theIn first the secondquarter quarter of 2020 (April (January to June), to March) a reduction compared of 15.4% to the was same registered, quarter in 2019which (Figure comprised 6B). In a the reduction second of quarter patient (April numbers to June), as well a reduction as treatments of 15.4% during was the registered, first whichlockdown. comprised The third a reduction quarter (July of patient to September) number showeds as well a recoveryas treatments with 101.3% during of the the first lockdown.same quarter The in third 2019. quarter (July to September) showed a recovery with 101.3% of the same quarter in 2019. 4. Discussion 4. DiscussionDuring the first six months of the pandemic, a drop in patients was observed in the urgent dental care unit of the Department of Conservative Dentistry and Periodontology in MunichDuring as well the as first in Bavarian six months dental of practicesthe pandemic as reported, a drop by in the patients KZVB.A was similar observed decrease in the urgentin patients dental was care observed unit of in the several Department countries of [16 Conservative,17]. In March, Dentistry this drop and was Periodontology particularly inevident Munich for as routine well as checkups in Bavarian and electivedental practices treatments as that reported were notby painthe KZVB. driven. A Fear similar decreaseof contracting in patients COVID-19 was atobserved the dentist in several as well ascountries recommendations [16,17]. In toMarch, suspend this elective drop was particularlydental care byevident regulatory for routine institutions checkups during and the firstelective lockdown treatments have beenthat reportedwere not as pain driven.reasons [Fear6,18, 19of]. contracting However, routine COVID-19 checkups at arethe essential dentist foras preventivewell as recommendations dentistry and are to suspendassociated elective with increased dental care oral healthby regulatory [20,21], whereas institutions pain-triggered during the visits first are lockdown associated have beenwith reported poorer oral-health-related as reasons [6,18,19]. quality However, of life routine [22]. For checkups example, are in Switzerland,essential for routinepreventive dentistrydental checkups and are constitute associated 33% with of all dentalincreased appointments oral health under [20,21], normal whereas circumstances pain-triggered [23], visitscorresponding are associated to 26% with routine poorer checkups oral-health- includingrelated minor quality questions of life of all [22]. visitations For example, in the in Switzerland,present study routine before thedental public checkups awareness constitute of COVID-19 33% of in all February dental 2020appointments (baseline). under In normalthe United circumstances States, a similar [23], decreasecorresponding in routine to 26% visits routine was observed; checkups however, including it was minor accompanied by an increase in tooth extractions, which has been attributed to loss of questions of all visitations in the present study before the public awareness of COVID-19 insurance due to increasing unemployment [24]. in February 2020 (baseline). In the United States, a similar decrease in routine visits was observed; however, it was accompanied by an increase in tooth extractions, which has been attributed to loss of insurance due to increasing unemployment [24].

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As a consequence, it may be assumed that the pandemic could have long-term effects on the prevention and progression of oral diseases. This is underlined by the fact that only patients with acute pain remained constant, of which almost all received urgent interventions. Less acute but nevertheless existing dental problems were neglected [25,26], which was mainly noticed by a reduction in restorative, endodontic, as well as surgical interventions during the first lockdown. This change could have impaired people’s oral health within the respective time period and emphasizes the importance of a working oral health care system during a pandemic. It even has been reported that urgent interventions could not be administered because of limited access to dental practices [27]. In the beginning of the lockdown in Bavaria, the lack of sufficient basic PPE was the most common reason for closures of dental practices. Therefore, the provision and storage of PPE could help to avoid such closings in order to guarantee dental care during acute infection waves. Additionally, during the first lockdown, testing infrastructure was limited, and upon suspected COVID-19 infection, patients were required to be treated as such. This access limitation is especially true for rural areas, private dental practices, or upon the emergence of new diseases. Therefore, it has been suggested to implement a travel-, contact- and symptom- history questionnaire to screen for positive COVID-19 cases from the beginning of the pandemic [13,16,28]. Interestingly, the peak of registered patients with positive/suspected COVID-19 infections in the urgent dental care unit of our department coincided with the peak of infection numbers in Munich during the first wave, indicating the effectiveness and importance of such screening methods. In addition, telephone screening has been evaluated to reduce the number of dispensable dental visits effectively [29]. A systematic review has described gustatory dysfunctions and rarely oral mucosal lesions in COVID-19 positive patients [30]. In the urgent care unit, these symptoms were not the reason for seeking dental care but underlying preexisting dental problems that might have been avoidable by preventive checkups. For the treatment of these patients with positive/suspected COVID-19 infections, more intensive protection protocols for staff members have been indicated [4]. Although the risk of transmission has been evaluated to be very high for dental staff due to aerosol generating dental procedures and proximity to the respiratory tract during treatments [8,31,32], dental offices have not revealed higher infection numbers. Accordingly, an analysis of oral health care workers in Wuhan showed only few COVID-19 infections in dental staff, which could not be traced back to dental treatment itself [16]. During the first infection wave in April, only 0.72% of dental practices in Bavaria reported a positive COVID-19 infection of a staff member. A similar low percentage has been reported for dentists in the United States [33]. Accordingly, no staff contracting COVID-19 during work has been registered in our department so far nor have SARS-CoV-2-antibodies been found in July 2020 (unpublished study). Only three staff members contracted COVID-19 by 19 July 2021, and all could be traced back to private contacts. These data show that protocols established at the beginning of the pandemic [13] in conjunction with already high hygiene standards seem to provide a safe environment for oral health practitioners as well as patients.

5. Conclusions In conclusion, accessibility of dental care is necessary even under circumstances of high infection risk, and measures should be taken to guarantee its continuation. Data showed a distinct number of patients with positive/suspected COVID-19 infection needed predominantly pain-related urgent dental interventions. Measures established at the beginning of the pandemic include careful detection of patients with high COVID-19 risk and treatment of those with advanced PPE, which seem to have provided a safe environment for patients as well as oral health care providers. The storage as well as provision of PPE to dental practices by regulatory units could help to guarantee a stable and safe oral health care system in the future. Int. J. Environ. Res. Public Health 2021, 18, 7963 11 of 12

Supplementary Materials: The following are available online at https://www.mdpi.com/article/ 10.3390/ijerph18157963/s1, Figure S1: Dotplot of patients‘ age in urgent care pre-lockdown, during lockdown as well as post-lockdown. Author Contributions: Conceptualization, E.W. and K.C.H.; Data curation, E.W. and L.v.B.; Formal analysis, E.W.; Funding acquisition, R.H.; Investigation, E.W., L.v.B. and K.C.H.; Methodology, E.W.; Resources, L.v.B.; Supervision, R.H. and K.C.H.; Visualization, E.W.; Writing—original draft, E.W. and K.C.H.; Writing—review and editing, R.H. All authors have read and agreed to the published version of the manuscript. Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Institutional Review Board Statement: The study was conducted according to the guidelines of the Declaration of Helsinki and by the ethics committee of the Ludwig-Maximilians-Universität (No. 20-0904; 14.10.2021). Informed Consent Statement: Not applicable. Data Availability Statement: The data that support the findings of this study are available on reasonable request from the corresponding author. Acknowledgments: We would like to thank the KZVB for their fruitful collaboration. Additionally, we wish to thank the entire team in the urgent care unit for their support of the study during the pandemic. Conflicts of Interest: The authors declare no conflict of interest.

Abbreviations

PPE Personal protective equipment EID Emerging infectious disease SARS-CoV-2 Severe acute respiratory syndrome coronavirus 2 COVID-19 Coronavirus disease 19

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